#include <iostream>
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
int main(int argc, char** argv) {
int a,b,c,ans;
scanf("%d",&a);
scanf("%d",&b);
scanf("%d",&c);
ans=(a+b)*45/c;
printf("答案是%d\n",ans);
return 0;
}