1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31+33+35+37+39=1+39+3+37+5+35+7+33+9+31+11+29+13+27+15+25+17+23+19+21=40+40+40+40+40+40+40+40+40+40=400
