What is the output of this program with dynamic scoping rules

proc main

int x, z; proc A; proc B; int x, z; { x := 1; call C; print x; } (end B) proc C; int a, z; { x := 3; call D; print x; } (end C) { x := 2; call B; print x; } (end A) proc D; int x, b; proc E; int x; { x := 4; call F; print x; } (end E) proc F; { print x; x := 6; } (end F) { x := 5; call E; print x; } (end D) { x := 0; call A; print x; } (end main)