if __name__=='__main__':
    s=input().split()
    s[0]=list(s[0])
    s[1]=list(s[1])
    c=0
    b=0
    l=len(s[0])
    for i in range(l):
        if(s[0][i]==s[1][i]):
            b+=1
            s[0][i]='*'
            s[1][i]='*'
    for i in range(l):
        if(s[0][i]!='*'):
            for j in range(l):
                if(s[1][j]!='*' and s[0][i]==s[1][j]):
                    c+=1
                    s[0][i]='*'
                    s[1][j]='*'
                    break
    print('%dB%dC'%(b,c))