#include<stdio.h>
#include<math.h>//使用sqrt需要使用此头文件
int main()
{
    int a, b, c, d;
    float s, area, perimeter;
    scanf("%d %d %d", &a, &b, &c);
    if (a + b <= c || a + c <= b || b + c <= a)//三角形任意两边之和大于第三边
        printf("These sides do not correspond to a valid triangle");
    else
    {
        perimeter = a + b + c;
        s = (a + b + c) / 2.0;
        area = sqrt(s * (s - a) * (s - b) * (s - c));//sqrt指平方根计算
        printf("area = %.2f; perimeter = %.2f", area, perimeter);
    }
    return 0;
}