#include <stdio.h>

int main() {
    int l1, l2, c1, c2;
    scanf("%d", &c1);
    scanf("%d", &l1);
    scanf("%d", &c2);
    scanf("%d", &l2);
    if(l1*c1>l2*c2){
        printf("%d", l1*c1);
    }
    else{
        printf("%d", l2*c2);
    }
    return 0;
}