#include<stdio.h>

int main(){
    int num1,num2,num3;
    scanf("%d%d%d",&num1,&num2,&num3);
    
    if(num1<0 || num2<0 || num3<0){
        printf("Invalid input");
        return 0;
    }
    int sum;
    sum=num1+num2+num3;
    printf("%d",sum;)
    
    return 0;
}