1 files changed, 23 insertions, 0 deletions
diff --git a/euler73.c b/euler73.c
new file mode 100644
index 0000000..ea146b2
--- /dev/null
+++ b/euler73.c
@@ -0,0 +1,23 @@
+#include <stdio.h>
+
+int gcd(int a, int b)
+{
+	if (a==0)
+		return b;
+	else
+		return gcd(b%a, a);
+}
+
+int main()
+{
+	int count = 0;
+	for (int d = 5; d <= 12000; d++) {
+		int lo = d/3+1;
+		int hi = d/2;
+		for (int i = lo; i <= hi; i++) {
+			if (gcd(i, d)==1)
+				count++;
+		}
+	}
+	printf("%d\n", count);
+}