#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <cmath>
#include <queue>
#include <cstring>
#include <set>
#include <map>
using namespace std;
const int N = 1e5 + 6;
int d_8[8][2] = {{1, 2}, {1, -2}, {2, 1}, {2, -1}, {-1, 2}, {-1, -2}, {-2, 1}, {-2, -1}};
int d_4[4][2] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
int main()
{
  int n;
  cin >> n;
  string s;
  cin >> s;
  int len = s.size();
  if (n > 26)
    n %= 26;
  for (int i = 0; i < len; i++)
  {
    if (s[i] + n < 'z')
    {
      s[i] = s[i] + n;
    }
    else
    {
      s[i] = s[i] + n - 26;
    }
  }
  cout << s << endl;
  return 0;
}