#include <bits/stdc++.h>
// #include <windows.h>
// #include <bits/extc++.h>
// using namespace __gnu_pbds;
using namespace std;
//#pragma GCC optimize(3)
#define DB double
#define LL long long
#define ULL unsigned long long
#define in128 __int128
#define cint const int
#define cLL const LL
#define For(z,e1,e2) for(int z=(e1);z<=(e2);z++)
#define Rof(z,e1,e2) for(int z=(e2);z>=(e1);z--)
#define For_(z,e1,e2) for(int z=(e1);z<(e2);z++)
#define Rof_(z,e1,e2) for(int z=(e2);z>(e1);z--)
#define inint(e) scanf("%d",&e)
#define inll(e) scanf("%lld",&e)
#define inpr(e1,e2) scanf("%d%d",&e1,&e2)
#define in3(e1,e2,e3) scanf("%d%d%d",&e1,&e2,&e3)
#define outint(e) printf("%d\n",e)
#define outint_(e) printf("%d%c",e," \n"[i==n])
#define outint2_(e,e1,e2) printf("%d%c",e," \n"[(e1)==(e2)])
#define outll(e) printf("%lld\n",e)
#define outll_(e) printf("%lld%c",e," \n"[i==n])
#define outll2_(e,e1,e2) printf("%lld%c",e," \n"[(e1)==(e2)])
#define exc(e) if(e) continue
#define stop(e) if(e) break
#define ret(e) if(e) return
#define ll(e) (1ll*(e))
#define pb push_back
#define ft first
#define sc second
#define pii pair<int,int> 
#define pli pair<long long,int> 
#define vct vector 
#define clean(e) while(!e.empty()) e.pop()
#define all(ev) ev.begin(),ev.end()
#define sz(ev) ((int)ev.size())
#define debug(x) printf("%s=%d\n",#x,x)
#define x0 __xx00__
#define y1 __yy11__
#define ffo fflush(stdout)
cLL mod=998244353,G=404;
const ULL base=166686661;
// cLL mod[2]={1686688681ll,1666888681ll},base[2]={166686661ll,188868881ll};
template <typename Type> void get_min(Type &w1,const Type w2) { if(w2<w1) w1=w2; } template <typename Type> void get_max(Type &w1,const Type w2) { if(w2>w1) w1=w2; }
template <typename Type> Type up_div(Type w1,Type w2) { return (w1/w2+(w1%w2?1:0)); }
template <typename Type> Type gcd(Type X_,Type Y_) { Type R_=X_%Y_; while(R_) { X_=Y_; Y_=R_; R_=X_%Y_; } return Y_; } template <typename Type> Type lcm(Type X_,Type Y_) { return (X_/gcd(X_,Y_)*Y_); }
template <typename Type> Type md(Type w1,const Type w2=mod) { w1%=w2; if(w1<0) w1+=w2; return w1; } template <typename Type> Type md_(Type w1,const Type w2=mod) { w1%=w2; if(w1<=0) w1+=w2; return w1; }
void ex_gcd(LL &X_,LL &Y_,LL A_,LL B_) { if(!B_) { X_=1ll; Y_=0ll; return ; } ex_gcd(Y_,X_,B_,A_%B_); X_=md(X_,B_); Y_=(1ll-X_*A_)/B_; } LL inv(LL A_,LL B_=mod) { LL X_=0ll,Y_=0ll; ex_gcd(X_,Y_,A_,B_); return X_; }
template <typename Type> void add(Type &w1,const Type w2,const Type M_=mod) { w1=md(w1+w2,M_); } void mul(LL &w1,cLL w2,cLL M_=mod) { w1=md(w1*md(w2,M_),M_); } template <typename Type> Type pw(Type X_,Type Y_,Type M_=mod) { Type S_=1; while(Y_) { if(Y_&1) mul(S_,X_,M_); Y_>>=1; mul(X_,X_,M_); } return S_; }
template <typename Type> Type bk(vector <Type> &V_) { auto T_=V_.back(); V_.pop_back(); return T_; } template <typename Type> Type tp(stack <Type> &V_) { auto T_=V_.top(); V_.pop(); return T_; } template <typename Type> Type frt(queue <Type> &V_) { auto T_=V_.front(); V_.pop(); return T_; }
template <typename Type> Type bg(set <Type> &V_) { auto T_=*V_.begin(); V_.erase(V_.begin()); return T_; } template <typename Type> Type bk(set <Type> &V_) { auto T_=*prev(V_.end()); V_.erase(*prev(V_.end())); return T_; }
mt19937 gen(time(NULL)); int rd() { return abs((int)gen()); }
int rnd(int l,int r) { return rd()%(r-l+1)+l; }
int gt[1<<7];
map <int,char> gt2;
cint K=4;
ULL h[K+1];
mt19937_64 genll(time(NULL));
void main_init()
{
    gt['(']=1,gt[')']=-1,gt2[1]='(',gt2[-1]=')';
    gt['[']=2,gt[']']=-2,gt2[2]='[',gt2[-2]=']';
    gt['{']=3,gt['}']=-3,gt2[3]='{',gt2[-3]='}';
    gt['<']=4,gt['>']=-4,gt2[4]='<',gt2[-4]='>';
    For(i,0,4) h[i]=genll();
}
cint N=5.01e5;
int n,Q;
char str[N];
vct <int> q[N],q2[N];
deque <pair<int,ULL> > st;
ULL d[N];
multiset <ULL> mp;
int dep[N];
bool check(int l,int r)
{
    return (l>r?true:(gt[str[l]]>0&&gt[str[r]]<0&&dep[l]==dep[r]));
}
int solve(bool opt)
{
    // printf("solve\n");
    st={{0,(ULL)0}};
    int lst=0;
    if(opt) mp.clear();
    int ans=0,cnt=0;
    For(i,1,n)
    {
        int t=gt[str[i]];
        // printf("t=%d(%d)\n",t,gt[str[st.back().ft]]);
        dep[i]=dep[i-1]+(t>0)-(gt[str[i-1]]<0);
        if(t>0)
            st.pb({i,st.back().sc*base+h[t]});
        else if(gt[str[st.back().ft]]+t)
            lst=i,st={{0,(ULL)0}};
        else
            st.pop_back();
        // printf("i=%d,lst=%d,dep=%d\n",i,lst,dep[i]);
        for(auto j:q[i])
        {
            exc(j<=lst);
            int len=sz(st);
            int l=0,r=len,mid;
            while(l+1<r)
                (st[mid=l+r>>1].ft>=j?r:l)=mid;
            // printf("[%d,%d]:%d,%d,%d\n",j,i,l,r,len);
            // For_(j,1,len) printf("%d",st[j].ft); printf("\n");
            exc(!check(j,r<len?(st[r].ft-1):i));
            assert(j-i<=40);
            ULL hs=st.back().sc-st[l].sc*d[len-r];
            // For_(j,1,len) printf("%c",str[st[j].ft]); printf("\n");
            // printf("%lld\n",(LL)hs);
            if(opt) mp.insert(hs);
            else if(!hs) cnt++;
            else if(mp.find(hs)!=mp.end()) ans++,mp.erase(mp.find(hs));
        }
    }
    return (ans+(cnt>>1));
}
void main_solve()
{
    inpr(n,Q); scanf("%s",str+1);
    d[0]=1; For(i,1,n) d[i]=d[i-1]*base;
    For(i,1,n) q[i].clear(),q2[i].clear();
    while(Q--)
    {
        int x,y; inpr(x,y);
        q[y].pb(x),q2[n-x+1].pb(n-y+1);
    }
    solve(true);
    For(i,1,n) q2[i].swap(q[i]);
    reverse(str+1,str+n+1); For(i,1,n) str[i]=gt2[-gt[str[i]]];
    outint(solve(false));
}
int main()
{
    // ios::sync_with_stdio(0); cin.tie(0);
    // freopen("ex_hotspot3.in","r",stdin);
    // freopen("out.txt","w",stdout);
    // srand(time(NULL));
    main_init();
    int _; inint(_); For(__,1,_) // T>1 ?
        // printf("\n------------\n\n"),
        main_solve();
    return 0;
}
/*

*/