#include <stdio.h>

int main(void) {
	// your code goes here
    int x,b0,b1,b2,sum;
    scanf("%d",&x);
    b0=x/100;
    b1=x-b2*100;
    b2=x%10;
    sum=b0+b1+b2;
    printf("sum=%d",sum);
	return 0;
}