### Problem 71b. Sorting a subarray.

Given an array a[1] .. a[n] of names and ages, so that
each element a[k] is a pair,

a[k] = (string "Name", int age)

Given indexes L and R such that

1 <= L < R <= n.

Sort the subarray a[L] .. a[R] in increasing order of names
(or nondecreasing order if some names are equal), but do not change
the position of names outside of this sub-array. The sort should be
stable, namely, if two names are equal, then you may not interchange
their positions.

**Input**. The value of n, L, and R on the first line,
followed by one pair of values per line: name comma age.
For example.

5 2 5
Chua Sandra Jean, 20
Vidal Eric, 21
Sarmenta Luis, 35
Sarmenta Luis, 37
Tan-Rodrigo Mercedes, 36

**Output**. The entire array, printed out one name-age pair
per line, with the subarray sorted as required, and the rest of the
array left alone untouched.