How can I replace value with a series of increasing number in VsVim?

Question

I want to replace this part with a series of increasing number in VsVim.

Like so：

std::map<std::string, int> monthMap = {
    {"Jan", 0}, {"Janurary", 0}, {"Feb", 0}, {"February", 0}, {"Mar", 0}, {"March", 0}
};

I want to substitute all 0 for 1, 2, 3...

std::map<std::string, int> monthMap = {
    {"Jan", 1}, {"Janurary", 1}, {"Feb", 2}, {"February", 2}, {"Mar", 3}, {"March", 3}
};

How can I do this? Thanks!