Young individuals in uniforms are gathering under the flags of several different countries.
Young people gather under different coutnries' flags.
If the flags are different then there must be several of them.
exists e1 s1 s2 x1 x2 x3 x4 x5.(n_country(x5) & n_flag(x3) & under(e1,x3) & of(x3,x4) & -(x4 = x5) & n_country(x4) & a_several(s2) & Theme(s2,x4) & Actor(e1,x1) & v_gather(e1) & in(x1,x2) & n_uniform(x2) & n_individual(x1) & a_young(s1) & Theme(s1,x1))
exists e1 s1 x1 x2 x3 x4.(n_coutnry(x3) & under(e1,x4) & n_flag(x4) & of(x4,x2) & -(x2 = x3) & n_coutnry(x2) & Actor(e1,x1) & v_gather(e1) & n_people(x1) & a_young(s1) & Theme(s1,x1))