#include <bits/stdc++.h>   using namespace std;   char a[1000005];   char b[1000005];   int main(void) {     int n;     cin >> n >> (a + 1) >> (b + 1);     int ok = 0;     for (int i = 1; i <= n; ++i) ok += a[i] != b[i];     if (!ok) return cout <<  26 n , 0;     if (ok == 1) return cout <<  2 n , 0;     string k =   , l =   ;     for (int i = 1; i <= n; ++i) k += a[i];     for (int i = 1; i <= n; ++i) l += b[i];     int cnt = 0, ans = 0;     while (k[cnt] == l[cnt]) ++cnt;     k.insert(k.begin() + cnt, l[cnt]);     while (k[cnt] == l[cnt]) ++cnt;     l.insert(l.begin() + cnt, k[cnt]);     ans += (k == l);     k =   ;     l =   ;     for (int i = 1; i <= n; ++i) k += a[i];     for (int i = 1; i <= n; ++i) l += b[i];     cnt = 0;     while (k[cnt] == l[cnt]) ++cnt;     l.insert(l.begin() + cnt, k[cnt]);     while (k[cnt] == l[cnt]) ++cnt;     k.insert(k.begin() + cnt, l[cnt]);     ans += (k == l);     return cout << ans <<   n , 0;   }   