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#include <bits/stdc++.h>
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using namespace std;
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typedef long long ll;
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queue<ll> qq;
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vector<ll> hh(1010,0);
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int main(){
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    ll m,n;
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    cin>>m>>n;
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    ll cnt=0;
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    for(ll i=0;i<n;i++){
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        ll t;
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        cin>>t;
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        if(!hh[t]){
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            hh[t]=1;
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            qq.push(t);
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            cnt++;
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            while(qq.size()>m){
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                hh[qq.front()]=0;
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                qq.pop();
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            }
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        }
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    }
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    cout<<cnt<<endl;
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    return 0;
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}