#include<stdio.h>

#include<string>

using namespace std;

class Solution {

public:

string decodeString(string s) {

string ret;

for (int i = 0; i < s.length(); i++) {

int repeat = 0;

char c = s.at(i);

if (c >= '0' && c <= '9') {

while (c >= '0' && c <= '9') {

repeat = repeat * 10 + c - '0';

//printf("repate=%d, i=%d\n", repeat, i);

i++;

c = s.at(i);

}

int brackets = 1;

int j = i + 1;

while (j < s.length() && (brackets > 0)) {

char c2 = s.at(j);

if (c2 == '[') brackets++;

if (c2 == ']') brackets--;

j++;

}

string s2(s, i+1, j-i-2);

//printf("repeat=%d, s2=%s\n", repeat, s2.c_str());

i = j-1;

while (repeat > 0) {

repeat--;

ret += decodeString(s2);

}

} else {

ret += c;

}

}

return ret;

}

};

int main(int argc, char** argv)

{

Solution s;

string in(argv[1]);

printf("ret=%s\n", s.decodeString(in).c_str());

return 0;

}