【codeforces】Divisibility

#include<stdio.h>
typedef long long ll;
ll abs(ll x) {
return x>0?x:-x;
}
int main() {
ll k,a,b;
while(~scanf("%I64d%I64d%I64d",&k,&a,&b)) {
ll ans;
if(a>0&&b>0) {
ans=abs(b/k)-abs((a-1)/k);
} else if(a<0&&b<0) {
ans=abs(a/k)-abs((b+1)/k);
} else {
ans=abs(a/k)+abs(b/k)+1;
}
printf("%I64d\n",ans);
}
return 0;
}