Assuming the vector Strings hs n strings and the longest string is size m compute the time complexity for the following function:

(Result Big O notation simplified only)

string interleave(vector &Strings){
string answer = "";
int max = 0;
for(string x: Strings){
if(x.length() > max) max = x.length();
}
for(int i =0;i<max;i++){
for(int j=0;j<Strings.size();j++){
if(Strings[j].length() >= i){
answer += Strings[j][i];
}
}
}
return answer;
}