#include <stdio.h>
int sum(int n);
int main() {
int a,s;
scanf_s("%d",&a);
s = sum(a);
printf("%d",s);
return 0;
}
int sum(int n) {
int s=0;
for (n; n >= 1;n--) {
s += n;
}
return s;
}
#include <stdio.h>
int sum(int n);
int main() {
int a,s;
scanf_s("%d",&a);
s = sum(a);
printf("%d",s);
return 0;
}
int sum(int n) {
int s=0;
for (n; n >= 1;n--) {
s += n;
}
return s;
}