#include <stdio.h>
#include <math.h>

int main() {

    int a, b, c;

    printf("enter the three sides of your triangle.\n");
    scanf("%d%d%d", &a, &b, &c);

    double s = (a+b+c)/2.0;

    double area = sqrt(s*(s-a)*(s-b)*(s-c));

    printf("The area is %.2lf\n", area);
    return 0;
}