求助大佬，第三题不会

m = 1

s = s+m+n =3,n=3 >>s= s+m+n = 7,n = n-1 =2 >>s= s+m+n = 10,n = n-1 =1

m = 3

s = s+m+n =14,n=3 >>s= s+m+n = 20,n = n-1 =2 >>s= s+m+n = 25,n = n-1 =1

m = 5

s = s+m+n =31,n=3 >>s= s+m+n = 39,n = n-1 =2 >>s= s+m+n = 46,n = n-1 =1