#include <stdio.h>
int main() {
    int weight, speed;
    float balance,tilt, stability_index;
    
    scanf("%d", &weight);
    scanf("%d", &speed);
    scanf("5f", &balance)
    scanf("%f", &tilt);
    if (weight <=0 || speed <=0 || balance <=0 ||tilt <=0){
        printf("Invalid Input\n");
    }else{
        stability_index = (float)(weight = speed) / (balance =tilt);
        printf("%.2f\n", stability_imdex);
    }
    return 0;
}