inp = require('fs').readFileSync('/dev/stdin', 'utf8').split('\n')
N = inp.shift() * 1
S = inp.shift()
s = []
for (i=0; i<S.length; i++) {
    c = S[i].charCodeAt() + N
    if (c > 90) {
        c = c - 26
    }
    s[i] = String.fromCharCode(c)
}
console.log(s.join(''))