Go: package main

import "fmt"
	
func main()  {
	// ログインするたびに A 枚のコインが得られる
	// 7 日連続でログインすると，そのたびに，追加で B 枚
	// 少なくとも C 枚のコインを得るためにログインしなければならない回数
	var a, b , c int
	_, _ = fmt.Scan(&a, &b, &c)
	fmt.Printf("%d\n",calc(a, b, c))
}

func calc(a int, b int, c int) int{
	var day int
	for c > 0 {
		day++
		c -= a
		if day % 7 == 0 {
			c -= b
		}
	}
	return day
}

C++: 
#include <bits/stdc++.h>

class kin{
public:
	inline void open(FILE *,int);
	inline void close(void);
	inline void scan(void);
	inline kin &operator>>(char &);
	inline kin &operator>>(int &);
	inline kin &operator>>(long long &);
	inline kin &operator>>(double &);
	inline kin &operator>>(long double &);
	inline kin &operator>>(char *);
	template <class T> inline void get(T *,int);
private:
	FILE *fp;
	char *buf;
	int siz;
	int idx;
}in;

class kout{
public:
	inline void open(FILE *,int);
	inline void close(void);
	inline void print(void);
	inline kout &operator<<(char);
	inline kout &operator<<(int);
	inline kout &operator<<(long long);
	inline kout &operator<<(double);
	inline kout &operator<<(long double);
	inline kout &operator<<(const char *);
	template <class T> inline void put(T *,int,char,char);
private:
	FILE *fp;
	char *buf;
	int siz;
	int idx;
}out;

int main(int argc,char **argv){
	in.open(stdin,512);
	out.open(stdout,512);
	in.scan();
	int a,b,c;
	in>>a>>b>>c;
	int w=c/(a*7+b);
	c-=w*(a*7+b);
	if(c>a*7) c=a*7;
	out<<w*7+(c+a-1)/a<<'\n';
	out.print();
	in.close();
	out.close();
	return 0;
}

inline void kin::open(FILE *fpa,int siza){
	fp=fpa;
	buf=new char[siza];
	siz=siza;
	idx=0;
	return;
}
inline void kin::close(void){
	fp=nullptr;
	delete[] buf;
	buf=nullptr;
	siz=0;
	idx=0;
	return;
}
inline void kin::scan(void){
	int readsiz=(int)std::fread((void *)buf,(std::size_t)1,(std::size_t)siz,fp);
	if(readsiz!=siz) buf[readsiz]='\x00';
	idx=0;
	return;
}
inline kin &kin::operator>>(char &var){
	if(!buf[idx]){
		var='\x00';
		return *this;
	}
	var=buf[idx];
	if(++idx==siz) scan();
	if(++idx==siz) scan();
	return *this;
}
inline kin &kin::operator>>(int &var){
	if(!buf[idx]){
		var=0;
		return *this;
	}
	int sign=-1;
	if(buf[idx]=='-'){
		sign=1;
		if(++idx==siz) scan();
	}
	var=0;
	while(buf[idx]>='0'){
		var=var*10-(int)(buf[idx]-'0');
		if(++idx==siz) scan();
	}
	var*=sign;
	if(++idx==siz) scan();
	return *this;
}
inline kin &kin::operator>>(long long &var){
	if(!buf[idx]){
		var=0LL;
		return *this;
	}
	long long sign=-1LL;
	if(buf[idx]=='-'){
		sign=1LL;
		if(++idx==siz) scan();
	}
	var=0LL;
	while(buf[idx]>='0'){
		var=var*10LL-(long long)(buf[idx]-'0');
		if(++idx==siz) scan();
	}
	var*=sign;
	if(++idx==siz) scan();
	return *this;
}
inline kin &kin::operator>>(double &var){
	if(!buf[idx]){
		var=0.0;
		return *this;
	}
	double sign=-1.0;
	if(buf[idx]=='-'){
		sign=1.0;
		if(++idx==siz) scan();
	}
	var=0.0;
	while(buf[idx]>='0'){
		var=var*10.0-(double)(buf[idx]-'0');
		if(++idx==siz) scan();
	}
	if(buf[idx]=='.'){
		if(++idx==siz) scan();
		double dig=1.0;
		while(buf[idx]>='0'){
			var-=(double)(buf[idx]-'0')*(dig/=10.0);
			if(++idx==siz) scan();
		}
	}
	var*=sign;
	if(++idx==siz) scan();
	return *this;
}
inline kin &kin::operator>>(long double &var){
	if(!buf[idx]){
		var=0.0L;
		return *this;
	}
	long double sign=-1.0L;
	if(buf[idx]=='-'){
		sign=1.0L;
		if(++idx==siz) scan();
	}
	var=0.0L;
	while(buf[idx]>='0'){
		var=var*10.0L-(long double)(buf[idx]-'0');
		if(++idx==siz) scan();
	}
	if(buf[idx]=='.'){
		if(++idx==siz) scan();
		long double dig=1.0L;
		while(buf[idx]>='0'){
			var-=(long double)(buf[idx]-'0')*(dig/=10.0L);
			if(++idx==siz) scan();
		}
	}
	var*=sign;
	if(++idx==siz) scan();
	return *this;
}
inline kin &kin::operator>>(char *var){
	if(!buf[idx]){
		var[0]='\x00';
		return *this;
	}
	int ptr=0;
	while(buf[idx]>='!'){
		var[ptr++]=buf[idx];
		if(++idx==siz) scan();
	}
	var[ptr]='\x00';
	if(++idx==siz) scan();
	return *this;
}
template<class T>
inline void kin::get(T *var,int num){
	for(int i=0;i<num;++i) (*this)>>var[i];
	return;
}

inline void kout::open(FILE *fpa,int siza){
	fp=fpa;
	buf=new char[siza];
	siz=siza;
	idx=0;
	return;
}
inline void kout::close(void){
	fp=nullptr;
	delete[] buf;
	buf=nullptr;
	siz=0;
	idx=0;
	return;
}
inline void kout::print(void){
	std::fwrite((void *)buf,(std::size_t)1,(std::size_t)idx,fp);
	idx=0;
	return;
}
inline kout &kout::operator<<(char val){
	buf[idx]=val;
	if(++idx==siz) print();
	return *this;
}
inline kout &kout::operator<<(int val){
	if(val<0){
		buf[idx]='-';
		if(++idx==siz) print();
	}
	else val*=-1;
	char dig[10];
	int ptr=0;
	do{
		int tmp=val/10;
		dig[ptr++]=(char)-(val-tmp*10)+'0';
		val=tmp;
	}while(val);
	while(ptr--){
		buf[idx]=dig[ptr];
		if(++idx==siz) print();
	}
	return *this;
}
inline kout &kout::operator<<(long long val){
	if(val<0LL){
		buf[idx]='-';
		if(++idx==siz) print();
	}
	else val*=-1LL;
	char dig[19];
	int ptr=0;
	do{
		long long tmp=val/10LL;
		dig[ptr++]=(char)-(val-tmp*10LL)+'0';
		val=tmp;
	}while(val);
	while(ptr--){
		buf[idx]=dig[ptr];
		if(++idx==siz) print();
	}
	return *this;
}
inline kout &kout::operator<<(double val){
	if(val<0.0){
		buf[idx]='-';
		if(++idx==siz) print();
	}
	else val*=-1.0;
	double dig=1.0;
	while(val/dig<=-10.0) dig*=10.0;
	int tmp;
	while(dig>=1.0){
		buf[idx]=(char)-(tmp=(int)(val/dig))+'0';
		if(++idx==siz) print();
		val-=(double)tmp*dig;
		dig/=10.0;
	}
	buf[idx]='.';
	if(++idx==siz) print();
	for(int i=0;i<12;++i){
		buf[idx]=(char)-(tmp=(int)(val/dig))+'0';
		if(++idx==siz) print();
		val-=(double)tmp*dig;
		dig/=10.0;
	}
	return *this;
}
inline kout &kout::operator<<(long double val){
	if(val<0.0L){
		buf[idx]='-';
		if(++idx==siz) print();
	}
	else val*=-1.0L;
	long double dig=1.0L;
	while(val/dig<=-10.0L) dig*=10.0L;
	int tmp;
	while(dig>=1.0L){
		buf[idx]=(char)-(tmp=(int)(val/dig))+'0';
		if(++idx==siz) print();
		val-=(long double)tmp*dig;
		dig/=10.0L;
	}
	buf[idx]='.';
	if(++idx==siz) print();
	for(int i=0;i<16;++i){
		buf[idx]=(char)-(tmp=(int)(val/dig))+'0';
		if(++idx==siz) print();
		val-=(long double)tmp*dig;
		dig/=10.0L;
	}
	return *this;
}
inline kout &kout::operator<<(const char *val){
	for(int i=0;val[i];++i){
		buf[idx]=val[i];
		if(++idx==siz) print();
	}
	return *this;
}
template<class T>
inline void kout::put(T *val,int num,char spc,char end){
	--num;
	for(int i=0;i<num;++i) (*this)<<val[i]<<spc;
	(*this)<<val[num]<<end;
	return;
}

C++: #include <iostream>
using namespace std;
int main(void){
    int a=0;
    int b=0;
    int c=0;
    int d=0;
    int e=0;
    int f=0;
    int week=0;
    int g=0;
    cin>>a>>b>>c;
    if(c<=a*7+b){
        e=c/a;
        f=c%a;
        if(c>=a*7){
            cout<<7<<endl;
        }else{
            if(f==0){
             cout<<e<<endl;
            }else{
             g=e+1;
             cout<<g<<endl;
            }
        }    
    }else{
        week=c/(a*7+b);
        d=c%(a*7+b);
        e=d/a;
        f=d%a;
        if(d>=a*7){
            cout<<week*7+7<<endl;
        }else{
            if(f==0){
             g=week*7+e;
             cout<<g<<endl;
            }else{
             g=week*7+e+1;
             cout<<g<<endl;
            }
        }    
    }
}

C++: #include<iostream>

using namespace std;

int main(){
int A,B,C,temoti;
cin >> A;
cin >> B;
cin >> C;

temoti = 0;
int i=0,nissu=0;

while(temoti<C){
    i++;
    nissu++;
    if(i==7){
        temoti+=B;
        i=0;
    }
    temoti+=A;
}

cout <<nissu << endl;

return 0;

}

C++: #include <iostream>
using namespace std;
int main(void){
    int A,B,C,x,y,w;
    cin>>A>>B>>C;
    if(C<A*7){
     cout<<C/A+1;   
    }
    if(C>A*7){
        x=C/(7*A+B);
        y=C-x*(7*A+B);
        if(y%A==0){w=y/A;}else{w=y/A+1;}
        
        cout<<x*7+w;
    }
}