互质数的数量怎么做啊

Question

#include
using namespace std;
int solve(int n, int k) {
int a, b, m,q,i,j;
int s=0 ;
for (a = 2; a <= n; a++) {
for (m = 1; m <= n; m++) {
b = a + m * k;
if(b<=n)
{i=b;j=a;
j=i;i=b;b=j;}
do{
q=i%j;
i=j;
j=q;
}while(q!=0);
if(b==1){
s++;
}
}return s;
}

}
int main(){
int n, k;
cin >> n;
cin >> k;
cout << solve(n, k) << endl;
return 0;
}实在搞不懂哪里错了，为啥不能执行s++啊😭