#include <stdio.h>
int main()
{
int a,b,c;
scanf("%d",&a);
for (c=1;c<=a;c++)
{
b = b+c;
}
printf("%d",b);
return 0;
}
#include<stdio.h>
int main()
{
int a,b,c;
scanf("%d",&a);
for (b=1;b<=a;b++)
{
b=b+1;
}
printf("%d",b);
}9
#include<stdio.h>
int main()
{
int a,b,c;
scanf("%d",&a);
for (b=1;b<=a;b++)
{
c+=b;
}
printf("%d",c-16);
return 0;
}
================================================
#include<stdio.h>
int main()
{
int a,b;
scanf("%d",&a);
printf("%d",(1+a)*a/2);
}
#include<stdio.h>
int main()
{
int a,b,c;
scanf("%d",&a);
for (b=1;b<=a;b++)
{
if (b%2==0)
{
c+=b;
}
}
printf("%d",c);
}
==========================================
*/
#include<stdio.h>
int main()
{
int n,i,c;
scanf("%d",&n);
for (i=0;i<=n;i++)
{
if (i%10==1)
{
c+1;
}
}
printf("%d",c);
}