#include<stdio.h>
int main()
{    int x,y,z,t;
scanf("%d%d%d",&x,&y,&z);
if(y+2*z<=x&&1<=x&&x<=10*10*10*10*10&&1<=y&&y<=10*10*10*10*10&&1<=z&&z<=10*10*10*10*10)
{

t=(x-z)/(y+z);
printf("%d",t);
}
return 0;

}