Test a model with random data on GLPK

Im new on GLPK, I want to test my simple model, I use this comment to generate different random data:

param seed:=gmtime();
param u{(i,j) in E}:=(round(seed*Uniform01())) mod 40 ;

and I want to solve model for 100 times and obtain the average value of optimal value of objective function.

I don't know how to code iterated expression to repeat solving model in .mod file. Could you please help me?

This is my model:

###  VARIABLES  ###
var x{(i,j) in E} >= 0, <= u[i,j];
###  OBJECTIVE  ###
maximize Val: sum {(1,j) in E} x[1,j];
###  CONSTRAINTS  ###
subject to Balance {i in V diff {1,n}}:
  sum {(j,i) in E} x[j,i] = sum {(i,k) in E} x[i,k];
solve;