#!/usr/bin/python
from collections import Counter

s = 'GCP'
arr = map(int, raw_input().split())
counter = Counter(raw_input())
res = 0
for k, v in counter.items():
    winpos = s.index(k) - 1
    tmp = min(v, arr[winpos])
    res += tmp * 3
    v -= tmp
    drawpos = s.index(k)
    res += min(v, arr[drawpos])
print res