def get_z_from_el(element):
    """
    Very simple function that gives the atomic number AS A STRING when given the element symbol.
    Uses predefined a dictionnary.
    Parameter :
    element : string
    For the other way, see get_el_from_z
    """
    dict_name = {'Ru': '44', 'Re': '75', 'Ra': '88', 'Rb': '37', 'Rn': '86',
        'Rh': '45', 'Be': '4', 'Ba': '56', 'Bi': '83', 'Br': '35', 'H': '1',
        'P': '15', 'Os': '76', 'Hg': '80', 'Ge': '32', 'Gd': '64', 'Ga':
        '31', 'Pr': '59', 'Pt': '78', 'C': '6', 'Pb': '82', 'Pa': '91',
        'Pd': '46', 'Cd': '48', 'Po': '84', 'Pm': '61', 'Ho': '67', 'Hf':
        '72', 'K': '19', 'He': '2', 'Mg': '12', 'Mo': '42', 'Mn': '25', 'O':
        '8', 'S': '16', 'W': '74', 'Zn': '30', 'Eu': '63', 'Zr': '40', 'Er':
        '68', 'Ni': '28', 'Na': '11', 'Nb': '41', 'Nd': '60', 'Ne': '10',
        'Fr': '87', 'Fe': '26', 'B': '5', 'F': '9', 'Sr': '38', 'N': '7',
        'Kr': '36', 'Si': '14', 'Sn': '50', 'Sm': '62', 'V': '23', 'Sc':
        '21', 'Sb': '51', 'Se': '34', 'Co': '27', 'Cl': '17', 'Ca': '20',
        'Ce': '58', 'Xe': '54', 'Lu': '71', 'Cs': '55', 'Cr': '24', 'Cu':
        '29', 'La': '57', 'Li': '3', 'Tl': '81', 'Tm': '69', 'Th': '90',
        'Ti': '22', 'Te': '52', 'Tb': '65', 'Tc': '43', 'Ta': '73', 'Yb':
        '70', 'Dy': '66', 'I': '53', 'U': '92', 'Y': '39', 'Ac': '89', 'Ag':
        '47', 'Ir': '77', 'Al': '13', 'As': '33', 'Ar': '18', 'Au': '79',
        'At': '85', 'In': '49'}
    return int(dict_name[element])
