#include <stdio.h>
#include <stdlib.h>

int main()
{
    int n,m,j,k,p;
    while(~scanf("%d %d %d %d",&n,&m,&j,&k))
    {
        if(n*m>=k*j)
        {
            printf("%d\n",n*m);
        }
        else
        {
            printf("%d\n",k*j);
        }
    }
    return 0;
}
