#include<stdio.h>
int main (void)
{
    float a,b;
    char c;
    scanf("%f %f %c",&a,&b,&c);   
    if((c=='/')&&(b==0))
        printf("除数为0!");
    if((c=='+')||(c=='-')||(c=='*')||(c=='/'))
        switch(c)
        {
            case'+':printf("%f",a+b);break;
            case'-':printf("%f",a-b);break;
            case'*':printf("%f",a*b);break;
            case'/':printf("%f",a/b);break;
        }
    else
        printf("运算符号错误！");
    return 0;   
}