#include <iostream>
#include <vector>
 
template<typename T>
void print( const T &t ) 
{ 
    std::cout << t; 
}
 
template<typename T>
void print( const std::vector<T> &v ) 
{ 
    std::cout << '[';
    for( auto it = v.begin(); it != v.end(); ++it ) {
         if( it != v.begin() ) std::cout << ',';
         print( *it );
    }
    std::cout << ']';
}
 
 
int main() {
    std::vector<std::vector<int>> vv = { {1,2,3}, {4,5} };
    print(vv);
    return 0;
}

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