diff --git a/cpu/cache.c b/cpu/cache.c
new file mode 100644
index 0000000..824d1de
--- /dev/null
+++ b/cpu/cache.c
@@ -0,0 +1,45 @@
+#include <stdio.h>
+#define N 1024
+
+int gcd(int a, int b);
+int main() {
+	int n, d;
+	int i, j, k;
+	/* to use shorter types such as short is a BAD idea */
+	static int A[N][N], B[N][N], C[N][N];
+	int res = 0;
+
+	scanf("%d %d", &n, &d);
+	
+	for (i = 0; i < n; ++i)
+		for (j = i; j < n; ++j) {
+			//printf("%d %d\n", i ,j);
+			A[i][j] = gcd(i + 2,j + 2);
+			A[j][i] = A[i][j];
+		}
+	//printf("nya!\n");
+	for (i = 0; i < n; ++i)
+		for (j = i; j < n; ++j) {
+			//printf("%d %d\n", i ,j);
+			B[i][j] = gcd(n - i,n - j);
+			B[j][i] = B[i][j];
+		}
+
+	for (i = 0; i < n; ++i)
+		for (j = 0; j < n; ++j)
+			for (k = 0; k < n; ++k) {
+				//printf("i:%d, j^%d, k^%d\n", i, j, k);
+				C[i][j] += A[i][k] * B[j][k];
+			}
+	for (i = 0; i < n; ++i)
+		for (j = 0; j < n; ++j)
+			if (C[i][j] % d == 0)
+				++res;
+
+	printf("%d", res);
+}
+
+int gcd(int a, int b) {
+	return (a == 0) ? b : gcd(b % a, a);    
+}
+
diff --git a/cpu/flag.c b/cpu/flag.c
new file mode 100644
index 0000000..a41ec7e
--- /dev/null
+++ b/cpu/flag.c
@@ -0,0 +1,94 @@
+#include <stdio.h>
+#include <stdint.h>
+
+int check_registers(int a, int b, int max_reg);
+int main() {
+	int max_reg = 4;
+	int zf = 0, to_exec = 1;
+#ifdef REGISTERS
+	max_reg = REGISTERS;
+#endif
+	/* A, B, C, D. Indice - 5 */
+	uint8_t reg[4] = {0, 0, 0, 0};
+	int i;
+	uint8_t a, b;
+	uint8_t x;
+	
+	while (1) {;
+		scanf("%hhu", &x);
+#ifdef _DEBUG
+		printf("x:%hhu\n", x);
+#endif
+		if ((x & (1 << 7)) && !zf) {
+			to_exec = 0;
+			//zf = 0;
+		}
+		x &= 0x7F;
+#ifdef _DEBUG
+		printf("zf:%d, to_exec:%d\n", zf, to_exec);
+#endif
+		if (to_exec == 0) {
+			if ((x >= 1) && (x <= 3))
+				scanf("%hhu %hhu\n", &a, &b);
+			to_exec = 1;
+			zf = 0;
+			continue;
+		}
+
+		switch (x) {
+			case 0:
+				return 0;
+				break;
+			case 1:
+				scanf("%hhu %hhu\n", &a, &b);
+				if (check_registers(a, b, max_reg)) {
+					printf("-1\n");
+					return 0;
+				}
+				reg[a-5] += reg[b-5];
+				if (reg[a-5] == 0)
+					zf = 1;
+				else
+					zf = 0;
+				break;
+			case 2:
+				scanf("%hhu %hhu\n", &a, &b);
+				if(check_registers(a, b, max_reg)) {
+					printf("-1\n");
+					return 0;
+				}
+				reg[a-5] -= reg[b-5];
+				if (reg[a-5] == 0)
+					zf = 1;
+				else
+					zf = 0;
+				break;
+			case 3:
+				scanf("%hhu %hhu\n", &a, &b);
+				if(check_registers(a, 0, max_reg)) {
+					printf("-1\n");
+					return 0;
+				}
+				reg[a-5] = b;
+				if (reg[a-5] == 0)
+					zf = 1;
+				else
+					zf = 0;
+				break;
+			case 4:
+				for (i = 0; i < max_reg; ++i)
+					printf("%hhu ", reg[i]);
+				putchar('\n');
+				break;
+		}
+		to_exec = 1;
+	}
+}
+
+int check_registers(int a, int b, int max_reg) {
+	a -= 5;
+	b -= 5;
+	if ((a >= max_reg) || (b >= max_reg))
+		return 1;
+	return 0;
+}