import sys
#input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################
n = ni()
s = [ord(i)-65 for i in input()]
dp = [1] * 3
dp[s[0]] = 0
mod = 10**9+7
for i in range(1,n):
    ndp = [0] * 3
    ndp, dp = dp, ndp
    for j in range(3):
        if j == s[i]:
            dp[j] = ndp[j]
        else:
            dp[j] = ndp[(-j-s[i])%3]+pow(2,i,mod)
            dp[j] %= mod
    #print(dp)
print(dp[0])