a[9],b[9],s,i;main(t){for(scanf("%d%d%d",a+1,a,a+2);!(t=getchar()/7)?s+=fmin(a[i],b[i]),i--:a[i=(t+1)%3]*~-t?a[i]--,s+=3:++b[t-9];);s=!printf("%d",s);}