use std::{collections::{HashMap, HashSet}, io::stdin};

fn main() {
    let nm = input();
    let n = nm[0];
    let m = nm[1];
    let c = input();

    let mut g = vec![vec![]; n];
    for _ in 0..m {
        let uv = input();
        let u = uv[0] - 1;
        let v = uv[1] - 1;
        g[u].push(v);
        g[v].push(u);
    }

    let mut parent = (0..n).collect::<Vec<usize>>();
    let mut visited = vec![false; n];
    for start in 0..n {
        if visited[start] {
            continue
        }

        let mut stack = vec![start];
        while !stack.is_empty() {
            let cur = stack.pop().unwrap();
            visited[cur] = true;
            parent[cur] = start;
    
            for &nxt in &g[cur] {
                if c[cur]==c[nxt] && !visited[nxt] {
                    stack.push(nxt);
                }
            }
        }
    }

    let mut map = HashMap::new();
    for i in 0..n {
        map.entry(c[i]).or_insert_with(|| vec![]).push(i); 
    }

    let mut ret = 0;
    for (_color, curs) in map {
        let mut groups = HashSet::new();
        for &cur in &curs {
            groups.insert(parent[cur]);
        }
        ret += groups.len()-1;
    }

    println!("{}", ret);
}

fn input() -> Vec<usize> {
    let mut buf = String::new();
    stdin().read_line(&mut buf).unwrap();
    buf.split_whitespace().map(|token| token.parse().unwrap()).collect::<Vec<usize>>()
}

pub struct UnionFind {
    parent: Vec<usize>,
    size: Vec<usize>,
}