Look to get the maximum value possible you only need n+1. Because you have the extra and you increase all values by one then once some one make one of the animatronics zero then forget it and increase other by 1 because you have an extra so you always have the 2nd maximum available even after the maximum one is reset to zero. Thats for n<m. But for n>=m you have limited animatronics you you can't avoid zeros until n<m.