include <stdio.h>

int main() {

int a, b, c, d, e, m, h;
scanf("%d", &a);
e = a % 10;
a = a / 10;
d = a % 10;
a = a / 10;
c = a % 10;
a = a / 10;
b = a % 10;
a = a / 10;
m = a % 10;
h = d + b + e + c;
printf("%d", h);

return 0;

}